MEMS optical latching switch

ABSTRACT

An optical micro-electro-mechanical system (MEMS) switch is disclosed. In a preferred embodiment the optical MEMS switch is used as an M×N optical signal switching system. The optical MEMS switch comprises a plurality of optical waveguides formed on a cantilever beam platform for switching optical states wherein the state of the optical switch is changed by a system of drive and latch actuators. The optical MEMS device utilizes a latching mechanism in association with a thermal drive actuator for aligning the cantilever beam platform. In use the optical MEMS device may be integrated with other optical components to form planar light circuits (PLCs). When switches and PLCs are integrated together on a silicon chip, compact higher functionality devices, such as Reconfigurable Optical Add-Drop Multiplexers (ROADMs), may be fabricated.

[0001] This application claims the benefit of Provisional PatentApplication No. 60/456,063, filed Mar. 19, 2003.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] Attention is directed to copending provisional applications USProvisional Application No. 60/456,086, filed Mar. 19, 2003, entitled,“M×N Cantilever Beam Optical Waveguide Switch” and US ProvisionalApplication No. 60/456,087, filed Mar. 19, 2003, entitled, “MEMSWaveguide Shuttle Optical Latching Switch”. The disclosure of each ofthese copending provisional applications are hereby incorporated byreference in their entirety.

BACKGROUND

[0003] This invention in embodiments relates to microelectromechanicalsystem (MEMS) switches and more particularly to multiple state opticallatching switches.

[0004] The telecommunications industry is undergoing dramatic changeswith increased competition, relentless bandwidth demand, and a migrationtoward a more data-centric network architecture. First generationpoint-to-point wave division multiplex systems have eased the trafficbottleneck in the backbone portion of a network. As a new cross-connectarchitecture moves the technology closer to the subscriber side of thenetwork, operators are challenged to provide services at the opticallayer, calling for more flexible networks that can switch and reroutewavelengths. This is placing great emphasis and demand for wavelengthagile devices.

[0005] The need to provide services “just in time” by allocation ofwavelengths, and further migration of the optical layer from thehigh-capacity backbone portion to the local loop, is driving thetransformation of the network toward an all optical network in whichbasic network requirements will be performed in the optical layer.

[0006] The optical network is a natural evolution of point-to-pointdense wavelength division multiplexing (DWDM) transport to a moredynamic, flexible, and intelligent networking architecture to improveservice delivery time. The main element of the optical network is thewavelength (channel), which will be provisioned, configured, routed, andmanaged in the optical domain. Intelligent optical networking will befirst deployed as an “opaque” network in which periodicoptical-electrical conversion will be required to monitor and isolatesignal impairments. Longer range, the optical network will evolve to a“transparent” optical network in which a signal is transported from itssource to a destination totally within the optical domain.

[0007] A key element of the emerging optical network is an opticaladd/drop multiplexer (OADM). An OADM will drop or add specificwavelength channels without affecting the through channels. Fixed OADMscan simplify the network and readily allow cost-effective DWDM migrationfrom simple point-to-point topologies to fixed multi-pointconfigurations. True dynamic OADM, in which reconfiguration is done inthe optical domain without optical-electrical conversion, would allowdynamically reconfigurable, multi-point DWDM optical networks. Thisdynamically reconfigurable multi-point architecture is slated to be thenext major phase in network evolution, with true OADM an enablingnetwork element for this architecture.

[0008] On chip integration of optical switching and planar lightcircuits has the potential to greatly reduce the size and manufacturingcosts of multi-component optical equipment such as ReconfigurableOptical Add/Drop Multiplexers (ROADMs). Current costs for ReconfigurableOptical Add/Drop Multiplexers (ROADMs) are $1,000 per channel, limitingtheir use to long-haul optical telecommunications networks. In order toextend their use into the metropolitan network the cost will need to bedecreased by an order of magnitude to $100 per channel, withoutsacrificing performance.

[0009] One solution to decreasing cost is through the integration ofcomponents, where the primary cost savings will be in packaging. Anumber of approaches are being pursued for optical integration usingPlanar Light Circuit (PLC) technologies. The majority of approaches usea silica-on-silicon platform with the ROADM formed from the integrationof silica Arrayed Waveguide Gratings (AWG's) for multiplexing anddemultiplexing, with Thermo-Optic (TO) switches for performing theadd/drop and pass of the demultiplexed signal. The use of a low-indexcontrast silica-on-silicon platform severely limits the yield of thesecomponents due to the requirement for uniform thick oxide films overlarge areas to form the waveguides. The use of TO switches limits theextensibility due to high-power requirements and thermal cross-talk.

[0010] A number of different materials and switching technologies arebeing explored for fabricating chip-scale photonic lightwave circuitssuch as AWG's for demultiplexers and multiplexers, Variable OpticalAttenuators (VOA's) and Reconfigurable Optical Add-Drop Multiplexers(ROADMs). The main material platforms include silica wafers,silica-on-silicon substrates using both thin film deposition and waferbonding techniques, polymer waveguides defined on silicon substrates,and silicon-on-insulator substrates. The main switching technologiesinclude Mach-Zehnder interferometers based on either a thermo-optic orelectro-optic effect, and MEMS mechanical waveguide switches.

[0011] While silica waveguides have optical properties that are wellmatched to the optical properties of conventional single mode fibers,and thus couple well to them, they require thick cladding layers due tothe low index of refraction contrast between the waveguide core andcladding materials, making them difficult to fabricate using planarprocessing techniques for fabrication and integration with other on-chipoptical devices. The low index of refraction contrast, Δn, between coreand cladding also requires large bending radii to limit optical lossduring propagation through the photonic lightwave circuit, leading tolarge chip footprints and low die yields (<50%).

[0012] In addition, silica based waveguide switches are typically basedon Mach-Zehnder interference using thermo-optic effects, that have alimited Extinction Ratio (ER) of around 25-30 dB, require significantpower due to the low thermo-optic coefficient of silica, have problemswith thermal cross-talk between the different optical channels and havea sinusoidal rather than a digital optical response. They also losetheir switching state when power is lost.

[0013] What is needed is a Silicon-On-Insulator (SOI) platform formonolithically integrating optical, mechanical and electrical functions.The use of a silicon platform enables fabrication of components usingthe vast infrastructure and process development available forsemiconductor IC manufacturing at silicon foundries. By fabricating theMEMS switches and waveguides in the same material, single crystalsilicon, there are no stress and strain issues as exist withheterogeneous materials sets such as silica-on-silicon. Fabrication insilicon also allows for integration with CMOS microelectronics forcontrol and sensing capabilities, and for free-carrier plasma dispersioneffects to enable signal leveling using integrated VOA's. The high indexcontrast of silicon (n=3.5) enables the ridge waveguide structures tomake tight turns with minimum optical bending loss, decreasing overallchip size to centimeter dimensions.

SUMMARY

[0014] An optical micro-electro-mechanical system (MEMS) switch isdisclosed. In a preferred embodiment the optical MEMS switch is used asan M×N optical signal switching system. The optical MEMS switchcomprises a plurality of optical waveguides formed on a flexiblecantilever beam platform for switching optical states wherein the stateof the optical switch is changed by a system of drive and latchactuators. The optical MEMS device utilizes a latching mechanism inassociation with a thermal drive actuator for aligning the cantileverbeam platform. In use the optical MEMS device may be integrated withother optical components to form planar light circuits (PLCs). Whenswitches and PLCs are integrated together on a silicon chip, compacthigher functionality devices, such as Reconfigurable Optical Add-DropMultiplexers (ROADMs), may be fabricated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings are not to scale and are only for purposes ofillustration.

[0016]FIG. 1 is a cut away top plane view of an optical MEMS (MicroElectro Mechanical System) switch in accordance with the presentinvention;

[0017]FIG. 2 is an enlarged view of a portion of FIG. 1 for illustrativepurposes;

[0018]FIG. 3 is a side cross-sectional view of FIG. 2;

[0019]FIG. 4 is a graphically view of a timing diagram for controlling alatch and drive switch shown in FIGS. 1 and 2;

[0020]FIG. 5 is a top plane view showing the latch actuated to an openposition;

[0021]FIG. 6 is a top plane view showing the drive switch actuated to anovershoot position;

[0022]FIG. 7 is a top plane view showing the latching mechanism in thelatched position;

[0023]FIG. 8 is a cut away top plane view of an optical MEMS device witha “hook” hitch and latch teeth in accordance with another embodiment ofthe present invention;

[0024]FIG. 9A is an enlarged view of a portion of FIG. 8 detailing the“hook” hitch in an equilibrium state;

[0025]FIG. 9B is an enlarged view of a portion of FIG. 8 detailing thelatch teeth in an equilibrium state;

[0026]FIG. 10A is an enlarged view of a portion of FIG. 8 detailing the“hook” hitch in a first switch state;

[0027]FIG. 10B is an enlarged view of a portion of FIG. 8 detailing thelatch teeth in a first switch state;

[0028]FIG. 11A is an enlarged view of a portion of FIG. 8 detailing the“hook” hitch in a second switch state; and

[0029]FIG. 11B is an enlarged view of a portion of FIG. 8 detailing thelatch teeth in a second switch state.

DETAILED DESCRIPTION

[0030] Referring now to FIG. 1 there is shown a top plane view of anoptical MEMS (Micro Electro Mechanical System) switch 10. All opticaland moving mechanical components shown are fabricated in thesingle-crystal silicon device layer of a SOI wafer using a self-alignedprocess. The optical MEMS switch 10 utilizes a latching mechanism 20 inassociation with a thermal drive actuator 30 for aligning a flexiblecantilever beam platform 50 fixed at one end 58. The flexible cantileverbeam defines one or more movable waveguides for switching to one or morestationary waveguides defined on an optical slab 40. The componentsfabricated in the device layer of an SOI wafer may be released bysacrificial etching of the buried oxide layer. In use the optical MEMSswitch 10 may be integrated with planar light circuits (PLCs). Whenswitches and PLCs are integrated together on a silicon chip higherfunctionality devices, such as Reconfigurable Optical Add-DropMultiplexers (R-OADM), may be fabricated.

[0031] As shown in FIGS. 1 through 3, the optical switch 10 comprisesone or more thermal drive actuators 30 having associated duringfabrication one or more thermal latch actuators 21, each thermal latchactuator 21 supports translating latch teeth 22. The flexible cantileverbeam platform 50 defines a plurality of optical waveguides 52 and 54. Atether 34 connects the one or more thermal drive actuators 30 to theflexible cantilever beam platform 50. A linkage 28 connects the thermaldrive actuators 30 to a set of linkage teeth 24 wherein the linkageteeth 24 are contacted by the latch teeth 22 when the latch is engaged.The linkage teeth 24 and latch teeth 22 are spatially located todetermine one or more latched state positions wherein electrical stimuliis timed to actuate the thermal drive 30 and thermal latch actuators 21so as to switch between equilibrium and latched states as will be morefully described below.

[0032] The optical MEMS switch 10 is applicable as an optical switch ina variety of applications, such as optical fiber transmission networks,to route optical signals along various signal paths. Switches aretypically characterized by the number of input and output ports,referred to as M×N. For example, a 1×3 switch would switch one inputbetween three outputs. M×N switches have previously been implementedusing waveguide shuttles or by cascading a series of M 1×N cantileverswitches. While shuttle switches can provide the M×N switchingfunctionality, they require at least two gaps in the optical pathway,which leads to increased optical losses. Similarly, a series of Mcascaded cantilever switches would have M optical gaps which leads toincreased optical losses for M>1. By fabricating an M×N cantilever beamwaveguide switch, where a cantilever beam carrying M waveguides isdeflected rather than a waveguide shuttle, only one optical gap isrequired in the optical pathway, cutting the optical loss associatedwith propagation through the gaps in half. Alternatively M cantileverbeams, each carrying a single waveguide, can be flexibly connected sothat they all actuate together. Furthermore, reflections from the twogaps associated with a shuttle can cause additional losses due tointerference.

[0033] Turning once again to FIGS. 1 through 5 there is shown theoptical switch 10 with two optical waveguides 52 and 54 formed on theflexible cantilever beam platform 50 for switching between twostationary optical waveguides 42 and 44, respectively. Thisconfiguration enables two optical signals to be switched at the sametime. By including additional optical waveguides, additional signals maybe switched simultaneously. The ability to switch multiple signals atthe same time is important in many optical applications. For example, inan R-OADM (Reconfigurable Optical Add/Drop Multiplexer), when an inputsignal is dropped, a new signal can be added to the output. Since theadd/drop function always occurs simultaneously, it is possible todecrease the number of required optical switches by implementing asingle cantilever switch that performs the add drop function on both theinput signal, sending it to the drop line, and the add signal, sendingit to the switch's output. Referring to FIG. 3, the optical multiplestate latching switch 10 uses oxide anchors 56 to attach components tothe substrate 60. As well known in the art, polysilicon anchors can beutilized instead of oxide. Polysilicon can also be used to fabricatedimples, as commonly practiced in MEMS to avoid stiction.

[0034] Referring now to FIG. 4 there is graphically illustrated thetiming sequence of the signals used to actuate the drive and latchmechanisms for the 2×2 switch illustrated in FIG. 1, where the voltagesare labeled in FIG. 4 assuming the potential of the handle wafer or basesubstrate 60 is zero. The first portion of the timing diagram shows thelatching sequence. The first step in the latching sequence is to apply avoltage +V1 to one end 26 of each latch actuator 21, and a voltage −V1to the other end 45 of each latch actuator 21. The voltages on the latchactuators induce ohmic heating in the actuator beams, causing thermalexpansion and the subsequent opening (direction 27) of the latch asshown in FIG. 5. While the latch actuator voltage is still applied, thedrive actuator 30 is stimulated with a voltage +V2 at one end 31 and avoltage −V2 at the other end 33.

[0035]FIG. 6 shows how the resulting thermal expansion of the driveactuator 30 is sufficient to move the flexible cantilever beam platform50 and linkage 28 far enough to the right for the linkage teeth 24 to bewell to the right side of the latch teeth 22. Next the latch actuatorvoltages return to zero, and the latch closes. To finish the latchingsequence, the drive actuator voltages return to zero. As the driveactuator cools, the linkage teeth 24 are drawn in tension (direction 37)against the latch teeth 22 which holds the switch in the desired latchedposition as shown in FIG. 7. To return the switch to its original state,the same sequence of voltages are applied in the reverse timing, asshown in the unlatch portion of FIG. 4. Unlike switches with no latchingcapability, the optical MEMS latching switch 10 only consumes powerduring a change of state, and preserves its state, even if power isinterrupted.

[0036] It should be noted that, although the timing diagram shown inFIG. 4 depicts square wave voltage pulses, this depiction is meant to beillustrative only of the basic timing, and does not preclude the use ofother waveforms. Furthermore, the voltages applied to the thermalactuators need not be symmetric about zero. However, the use of equalbut opposite polarity pulses, as described above, results in a constantzero voltage at the center of each actuator throughout the latch andunlatch cycle, which reduces electrostatic forces between the actuatorsand the handle wafer 60.

[0037] A logic table for the 2×2 switching function is as follows:

[0038] State One: Add/Drop function, as shown in FIG. 5

[0039] The left movable waveguide 52 (input) is optically aligned to theleft stationary waveguide 42 (drop).

[0040] The right movable waveguide 54 (add) is optically aligned to theright stationary waveguide 44 (output).

[0041] State Two: Pass function, as shown in FIG. 7

[0042] The left movable waveguide 52 (input) is optically aligned to theright stationary waveguide 44 (output).

[0043] In order to change from state one to state two, a force F can beapplied by a thermal drive actuator 30. In order to deflect the free endby a distance δx, a force F must be applied where F is given by:

F=(Ea ³ b/4L ³)δx

[0044] Where E is Young's modulus (E=1.65×10⁵ μN/μm² for single crystalsilicon), a is the thinner cross-sectional dimension of the beam 21, bis the thicker cross-sectional dimension of the beam and L is the lengthof the beam. For example, a 1000 μm long beam that is 5 μm thick and 20μm wide would require a force of 13.2 μN to deflect the free end by 8μm, which is sufficient deflection to switch a cantilever beam with two4 μm waveguides.

[0045] The switching force F can be applied to the free end of thecantilever beam 50, or at an intermediate location, or locations asrequired. The switch can also be actuated in the opposite direction byapplying a force F from the thermal drive actuator 30 in the oppositedirection. In some cases it may be preferable to not use the equilibriumposition of the cantilever beam, since these do not have a strongrestoring force that returns them to this position since the cantileverbeam may be quite long and flexible. Instead only deflected positionsmay be desirable to use. In addition, it may be advantageous to anglethe receiving waveguides to better match the direction of propagation ofthe light leaving the deflected cantilever beam.

[0046] Since the cantilever beam carrying multiple waveguides could bewider than it is thick, it could suffer undesirable out of planedeflections since it is less stiff out of plane than it is in plane, aspredicted by the formula

K=(Ea/4)(b/L)³

[0047] As an example for a beam that is 5 μm thick and 20 μm wide, theratio of the stiffness in the horizontal direction of the verticaldirection is (20/5)². The beam is 16 times stiffer in the horizontaldirection relative to the vertical direction.

[0048] In order to avoid out of plane deflections the appropriatelocation along the cantilever beam 50 may be attached to a switch tether34 so as to minimize these out of plane deflections. The beam's widthmay also be decreased at certain points to decrease its stiffness in thehorizontal direction (e.g. serrated). Joints can be added to make thebeam more flexible in the horizontal direction. The beam can bedeflected bi-directionally to decrease the magnitude of the requireddeflection. The beam can be thickened or stiffened to make it lessflexible in the out-of-plane direction (e.g. by making the beam thickeror by adding super structures such as additional beams).

[0049] The switches and the waveguides are made together on a singlecrystal silicon wafer using widely available semiconductor processingequipment. Such on-chip integration avoids the complex alignment issuesassociated with manually connecting different and larger components withoptical fibers, and avoids the cost and space associated withmanufacturing, assembling and packaging the separate components ofoptical switches. On-chip integration with other components can drivedown the cost of manufacturing switches and installation of thesecomplicated devices by a factor of ten or more. Currently, thesecomponents cost over $1,000 per channel.

[0050]FIGS. 8 through 11 shows two extensions 100 of the systemembodiment depicted in FIG. 1. The first extension is to a higher orderof switching, from 2×2 in FIG. 1 to 2×3 in FIG. 8. The second optionshown in FIG. 9A is the introduction of a “hook”-hitch 132 and 134instead of a simple tether. These two extensions are discussed below.

[0051] To increase the system from a 2×2 switch to a 2×3 switch, twoadditional elements are required. The first is another stationarywaveguide platform defining stationary waveguides 142, 144 and 146respectively. The second element is an extra pair of teeth 25 on thelinkage 28 located after the teeth set 24 as shown in FIG. 9B. For theinitial state of the 2×3 switch, the latch teeth are disengaged as shownin FIG. 9B. In this position, the right most moveable waveguide 154 isaligned with the left most stationary waveguide 142 as shown in FIGS. 8and 9A. Using an actuation sequence similar to the latching phase shownand described in FIG. 4, the switch can be moved to a second state asshown in FIG. 10B. Here the latch teeth 22 defined by the latch actuator21 engage between the pair of teeth 24 and 25 on the linkage 28, and thetwo movable waveguides 152 and 154 are align with the left most pair ofstationary waveguides 142 and 144 respectively, as shown in FIG. 10A. Athird state can be achieved by executing another latching sequence withhigher voltages on the drive. In this state, depicted in FIGS. 11A and11B, the latch teeth 22 engages behind the pair of linkage teeth 24 andthe two moveable waveguides 152 and 154 now align with the right mostpair of stationary waveguides 144 and 146.

[0052] The 2×3 switch example discussed above, is one embodiment of thegeneral ability to achieve N×M switching for small values of N and M.Each N×M configuration requires a sufficient number of fixed and movablewaveguides. Further design considerations may be accounted for toachieve the desired set of switch positions. These include the initialrelative alignment and spacing of the moveable and stationarywaveguides, as well as, the number and relative location of the linkageteeth.

[0053] The second option shown in FIGS. 8 through 11 is the substitutionof an interlocking “hook” hitch 132 and 134 for the tether 34. Dependingon the embodiment and fabrication processes employed, the “hook” hitchmay be used to mitigate the affects of stresses that may degrade theswitch performance. For example, if the process were to induce stress inthe drive actuator 30, the stress could be transferred through a tether34, and impact the equilibrium state alignment of the waveguides. The“hook” hitch mechanically decouples the drive actuator 130 from themoveable waveguide platform 150 in the equilibrium state, therebyeliminating any transferred stress that would induce a misalignment inthe equilibrium state.

[0054] The “hook” hitch also mitigates stresses that occur in latchedstates that lead to undesirable rotations in the linkage. As theunanchored end of the cantilevered waveguide platform is pulled to theright, the translational motion of the platform is accompanied by asmall clockwise rotation due to the bending of the cantileveredplatform. If a simple tether is used, the rotation of the waveguideplatform bends the tether 34, which in turn causes a counter clockwiserotation of the linkage 28, and may also asymmetrically distort thedrive actuator. The rotation of the linkage and asymmetric distortion ofthe actuator is most severe in systems that require largerdisplacements. The “hook” hitch, however, provides a good countermeasure for these issues. As seen in FIG. 11A the “hook” hitchcombination 132 and 134 provides a pivot point at the contact pointbetween the left hook 134 attached to the cantilevered waveguide beamplatform and the right hook 132 attached to the thermal drive actuator.The “hook” hitch thereby decouples the rotational motion of thecantilevered waveguides from the rest of the system, allowing thelinkage and drive to operate without induced rotations.

[0055] The invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respect only as illustrative andnot restrictive. The scope of the invention is, therefore, indicated bythe appended claims, rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. An optical multiple state latching switch,comprising: one or more drive actuators; one or more latch actuatorswith associated latch teeth; a flexible cantilever beam platformdefining a plurality of optical waveguides; a tether connecting said oneor more drive actuators and said flexible cantilever beam platform; alinkage defining one or more linkage teeth connecting to said one ormore drive actuators located for engaging said associated latch teethlocated to determine one or more latched state positions; and electricalstimuli timed to actuate said one or more drive and latch actuators soas to change between equilibrium and latched states.
 2. The opticalmultiple state latching switch according to claim 1, wherein saidflexible cantilever beam platform is pulled or pushed by said one ormore drive actuators.
 3. The optical multiple state latching switchaccording to claim 1, wherein said flexible cantilever beam platform canbe deflected bi-directionally.
 4. The optical multiple state latchingswitch according to claim 1, wherein said flexible cantilever beamplatform has mechanical features to increase or reduce the stiffness ofsaid flexible cantilever beam platform.
 5. The optical multiple statelatching switch according to claim 1, wherein said latching switch isfabricated in the device layer of an SOI wafer.
 6. The optical multiplestate latching switch according to claim 1, wherein said latching switchis fabricated in the device layer of an SOI wafer and released bysacrificial etching of the buried oxide layer.
 7. The optical multiplestate latching switch according to claim 1, wherein said electricalstimuli to said one or more drive actuators are biased to reduceelectrostatic forces acting on said actuator.
 8. The optical multiplestate latching switch according to claim 1, wherein said electricalstimuli to said actuators are biased to reduce or eliminate voltagedifferences between contacting surfaces on said latch teeth and saidlinkage teeth.
 9. An optical multiple state latching switch, comprising:one or more drive actuators; one or more latch actuators definingassociated latch teeth; a flexible cantilever beam platform withassociated plurality of optical waveguides; a hook-hitch for engagingsaid drive actuator and said flexible cantilever platform; a linkageconnecting said drive actuator to translating linkage teeth located todetermine one or more latched state positions; and electrical stimulitimed to actuate said one or more drive and latch actuators so as tochange between equilibrium and latched states.
 10. The optical multiplestate latching switch according to claim 9, wherein said flexiblecantilever beam platform is pulled or pushed by said drive actuators.11. The optical multiple state latching switch according to claim 9,wherein said flexible cantilever beam platform can be deflectedbi-directionally.
 12. The optical multiple state latching switchaccording to claim 9, wherein said flexible cantilever beam platform hasmechanical features to increase or reduce the stiffness of said flexiblecantilever beam platform.
 13. The optical multiple state latching switchaccording to claim 9, wherein said latching switch is fabricated in thedevice layer of an SOI wafer.
 14. The optical multiple state latchingswitch according to claim 9, wherein said latching switch is fabricatedin the device layer of an SOI wafer and released by sacrificial etchingof the buried oxide layer.
 15. An optical multiple state latchingswitch, comprising: one or more drive actuators; one or more latchactuators with associated latch teeth; a flexible cantilever beamplatform with associated optical waveguides; a hitch for engaging saiddrive actuators and said flexible cantilever beam platform defininglinkage teeth; a linkage defining one or more linkage teeth connectingto said one or more drive actuators located for engaging said associatedlatch teeth located to determine one or more latched state positions;and electrical stimuli timed to actuate said drive and latch actuatorsso as to change between equilibrium and latched states wherein saidelectrical stimuli to said actuators are biased to reduce or eliminatevoltage differences between contacting surfaces on said latch teeth andsaid linkage teeth.
 16. The optical multiple state latching switchaccording to claim 15, wherein said flexible cantilever beam platformhas mechanical features to increase or reduce the stiffness of saidflexible cantilever platform.
 17. The optical multiple state latchingswitch according to claim 15, wherein said flexible cantilever beamplatform has mechanical features to increase or reduce the stiffness ofsaid flexible cantilever platform.